1. Field of Invention
This invention relates to sound-insulating enclosures in which people sleep and to assuring adequate ventilation within these enclosures.
2. Review of Related Art
Many people live in places that are increasingly noisy. The modern world is permeated by: intrusive sound systems with powerful bass speakers that penetrate apartment walls, video games with loud explosions and sound effects, vehicles with thumping bass speakers, jet and train traffic at all hours of the day and night, sirens and heavy equipment, dogs that bark incessantly, and so forth. The list of noise pollution sources grows each year. High noise levels are bad enough during daylight hours, but can be especially devastating at night when one is trying to sleep. Lack of sleep due to environmental noise can wreak havoc on one's health, productivity, and overall quality of life. Sleep-disturbing noise can even come from one's own household. For example, loud snoring can have devastating effects on one's closest personal relationships.
Some people can afford to live in places that are far removed from the flight paths of major airports, but other people can not. Some people can afford to live far away from establishments that play loud music until the early morning hours, but other people can not. Some people can afford to have living arrangements with multiple bedrooms so that they do not have to choose between a close relationship and getting enough sleep to face the next day, but other people can not. For many people, sleep deprivation is a vicious cycle. Sleep deprivation hinders them from earning more income, the limited income limits their living options, and the limited living options result in more sleep deprivation. What can be done to break this cycle to help people to get a decent night's sleep in today's increasingly noisy world?
For all of these reasons, there is a significant and growing need for safe methods to reduce exposure to intrusive sounds so that people can get a decent night's sleep. There are methods in the related art that reduce a sleeper's exposure to environmental sounds. However, as we will discuss, these methods in the related art have significant limitations. A very-real unmet need remains. The invention disclosed herein is designed to meet this need in an innovative, safe, and useful manner. There does not appear to be anything in the prior art that anticipates this invention. This invention can help many people to avoid the devastation of chronic sleep deprivation on their health, relationships, productivity and overall quality of life.
There are six main categories of methods in the related art for reducing a sleeper's exposure to environmental noise: (1) active noise cancellation and noise masking; (2) sound-insulating panels or blankets that are described apart from their use in a specific type of sleeping enclosure; (3) sound-insulating sleeping structures with no explicit means for providing ventilation; (4) sound-insulating sleeping enclosures with direct passive ventilation through openings or holes; (5) sound-insulating sleeping enclosures with passive ventilation through air-permeable surfaces such as screens or nets; and (6) sound-insulating sleeping enclosures with active ventilation means such as fans or air pumps. We now briefly discuss each of these methods and their limitations. We then discuss how this present invention addresses these limitations, providing a superior and innovative solution for creating a sound-insulating sleeping enclosure with assured ventilation.
1. Active Noise Cancellation and Noise Masking
This category of methods for reducing a sleeper's exposure to environmental noise involves active generation of sounds to cancel or mask the environmental noise. Some of the many examples in the related art that appear to use noise cancellation or noise masking include U.S. Pat. Nos. 5,844,996 (Enzmann et al., 1998), and 6,014,345 (Schmadeka, 2000).
Noise cancellation involves monitoring environmentally-intrusive noise and then custom-generating “noise-canceling” sounds that have a symmetrically-opposite wave structure. Ideally, when the environmentally-intrusive sound waves and the custom-generated sound waves meet and overlap, their acoustic energies cancel each other out because their wave patterns are symmetrically-opposite to each other. Although appealing in theory, such cancellation can be difficult to do well in practice. For example, generation of sounds in order to cancel the environmental noise is not instantaneous. The environmental noise must be detected and analyzed. This creates a lag between the two sounds. If the environmental noise is relatively continuous, then this lag need not be a problem. However, if the environmental noise is intermittent or highly-variable, then the lag is a problem. The lagged sound waves do not cancel each other out.
One solution to address the lag problem is to have the noise monitor be closer to the noise source than the speaker that emits the custom-generated sounds and the sleeper's ear. However, this solution to the lag problem only works if the environmental noise consistently comes from the same direction. This solution breaks down when environmental noise comes from different directions. Noise-cancellation headphones can come close to canceling noise from any direction. However, many people do not like to wear headphones when they sleep and even headphones do not completely eliminate the lag problem. For these reasons, active noise cancellation is not an ideal solution for reducing sleepers' exposure to environmental noise.
A related approach is “noise masking.” Noise masking involves playing sounds that cover up, but do not cancel, intrusive environmental noise. Many noise masking devices create sounds with a broad-spectrum of frequencies, such as “white noise” or “pink noise,” that cover up noise at random. Other noise masking devices offer a menu of sounds from which the sleeper can select to cover up particular environmental sounds.
Both types of noise masking have limitations. Broad-spectrum random sounds (such as “white noise” or “pink noise”) may not be powerful or targeted enough to mask certain sounds, such as those with powerful bass frequencies. Sounds selected from a menu of sounds may have gaps between sounds or repetition in pre-recording sound loops that let the environmental sounds come through periodically or may themselves become annoying.
An overall limitation of using one sound to cover up another sound is analogous to using one smell to cover up another smell. Sometimes the sensory organ is just not fooled. For example, trying to cover up the smell of a wet dog with a flower scent might not fool one's nose. Trying to cover up a bass beat from the party next door with the sound of a bubbling waterfall might not fool one's ears. The combined effect can sometimes be doubly annoying, not relaxing.
2. Sound-Insulating Panels and Blankets Apart from a Specific Enclosure
This category of related art concerns sound-insulating panels and blankets. Such sound-insulating panels and blankets may be incorporated into various types of sound-insulating sleeping enclosures, but this art does not specify exactly how the panels and blankets are incorporated into particular designs of sound-insulating sleeping enclosures. Accordingly, related art in this category does not provide fully-developed methods of how to reduce a sleeper's exposure to external sounds. For example, this category of related art does not address how sound-insulating panels or blankets can be used to create a sound-insulating enclosure with assured ventilation. Nonetheless, it is worth noting this category for the sake of thoroughness and for the introduction of sound-insulating materials that may be used for sleeping enclosures.
Examples in the related art that appear to specify sound insulating panels or blankets apart from discussion of how they may be used in a specific enclosure for sleeping include the following: U.S. Pat. Nos. 4,513,041 (Delluc, 1985), 4,079,162 (Metzger, 1978), 3,748,799 (Tough et al., 1973), 5,018,328 (Cur et al., 1991), 5,411,623 (Shutt, 1995), 5,867,957 (Holtrop, 1999), 5,896,710 (Hoyle, 1999), 6,153,135 (Novitsky, 2000), and 7,063,184 (Johnson, 2006), and U.S. Patent Applications 20070125010 (Papakonstantinou, 2007) and 20090162599 (Rickards, 2009).
3. Sound-Insulating Structures with No Explicit Discussion of Ventilation
This category of methods for reducing a sleeper's exposure to external sounds involves partial enclosures that do not explicitly address how ventilation is provided. Generally, the degree to which they fully enclose the sleeper is sufficiently low that there remains plenty of passive ventilation from openings. Thus, explicit discussion of ventilation is not required. Some sound insulation is better than no sound insulation. Accordingly, these partial enclosures serve a purpose.
However, an opening that is sufficiently large to provide thorough passive ventilation is also sufficiently large to let a large amount of environmental sound energy reach the sleeper. For this reason, this category of sound-reducing means is not well-suited for thorough blocking of loud external sounds, particularly powerful bass sounds. Examples in the related art that appear to specify sound insulating structures with no explicit ventilation means include: U.S. Pat. Nos. 2,375,941 (Nostrand, 1945), 3,323,147 (Dean, 1967), 4,377,195 (Weil, 1983), 5,560,058 (Smith, 1996), and 6,446,751 (Ahuja et al., 2002).
4. Sound-Insulating Sleeping Enclosures with Ventilation Through Openings or Holes
This category of methods for reducing a sleeper's exposure to external sounds involves sleeping enclosures with openings or holes that allow direct, passive ventilation of the enclosure. The advantages and disadvantages of these enclosures are similar to those with structures with no explicit discussion of ventilation means. Some sound insulation is better than no sound insulation, but openings or holes that are sufficiently large to provide complete passive ventilation are also sufficiently large to let a large amount of environmental sound energy reach the sleeper. This category of means is not well-suited for blocking loud external sounds, particularly powerful bass sounds. Examples in the related art that appear to specify sound-insulating sleeping enclosures with openings or holes for ventilation include: U.S. Pat. Nos. 4,017,917 (Brown, 1977), 4,305,168 (Holter et al., 1981), 4,594,817 (McLaren et al., 1986), 5,669,088 (McNamee, 1997), and 6,308,466 (Moriarty, 2001).
5. Sound-Insulating Sleeping Enclosures with Ventilation Through Screens
This category of methods for reducing a sleeper's exposure to environmental sounds involves sleeping enclosures with air-permeable surfaces on their walls. These air-permeable surfaces may include screens, nets, or meshes. These air-permeable surfaces provide passive ventilation of the enclosure. However, like enclosures with direct openings or holes, they do not do a good job of blocking loud external sounds, particularly powerful bass sounds.
Examples in the related art that appear to specify sound-insulating sleeping enclosures with air-permeable surfaces (such as screens or nets) for ventilation means include: U.S. Pat. Nos. 4,641,387 (Bondy et al., 1987), 5,384,925 (Vail, 1995), 6,216,291 (Eads et al., 2001), 6,263,529 (Chadwick et al., 2001), 6,487,735 (Jacques et al., 2002), 6,694,547 (Vail, 2004), 6,772,458 (Ellen et al., 2004), 7,047,991 (Kline, 2006), 7,380,296 (Ellen et al., 2008), and 7,434,280 (Cyr, 2008), and U.S. Patent Application 20070294827 (Carr et al., 2007).
6. Sound-Insulating Sleeping Enclosures with Active Ventilation Means
This category of methods for reducing a sleeper's exposure to external sounds involves sleeping enclosures with active ventilation means. Active ventilation means may include electric fans, air pumps, or other means of actively moving fresh air into the sleeping enclosure. The use of active ventilation allows the enclosure to more completely enclose the sleeper. Thus, it can provide more thorough insulation from environmental sounds than is possible with enclosures that rely on passive ventilation means such as openings, holes, screens, or nets. Examples in the related art that appear to specify sound-insulating sleeping enclosures with active ventilation means include: U.S. Pat. Nos. 4,109,331 (Champeau, 1978), 4,129,123 (Smidak, 1978), 4,937,903 (Joly et al., 1990), 6,461,290 (Reichman et al., 2002), 6,508,850 (Kotliar, 2003), and 6,827,760 (Kutt et al., 2004).
A sound-insulated sleeping enclosure with active ventilation means can be very thorough in reducing exposure of the sleeper to environmental sounds if the following criteria are met: (1) the enclosure completely surrounds the sleeper without substantive gaps to external airspace in the walls of the enclosure; (2) the walls of the enclosure contain a partial vacuum or a highly-effective sound-insulating material; (3) the conduit that brings fresh air into the enclosure from the active ventilation means is relatively long or otherwise designed to significantly dampen transmission of external sound through the conduit; and (4) the active ventilation means itself is relatively quiet, insulated, and/or some distance from the enclosure.
Although sleeping enclosures that rely solely on active ventilation means can have significant advantages over the other five methods of reducing a sleeper's exposure to environmental sounds that have just been discussed, reliance on active ventilation means has a significant disadvantage that has not yet been satisfactorily addressed in the related art. If the active ventilation means fails due to power failure or mechanical failure, then ventilation within the enclosure stops as well. This potential safety risk for the sleeper has not yet been resolved. Reliance on active ventilation alone provides the best sound insulation, but also has the risk of ventilation stopping due to power failure or mechanical failure.
To conclude—passive ventilation does not involve the risk of ventilation stopping, but provides relatively poor sound insulation. Active ventilation by itself can provide thorough sound insulation, but involves the risk of ventilation stopping. This fundamental safety dilemma has not yet been solved in the related art. It is solved in an innovative and useful manner by the invention disclosed herein.